04-16548. Airworthiness Directives; Rolls-Royce plc RB211 Trent 800 Series Turbofan Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce plc (RR) models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines with low pressure (LP) compressor fan blades part number (P/N) FW18548, installed. This AD requires LP compressor fan blade replacement with new or previously reworked blades, or rework of the existing LP compressor fan blades. This AD results from a number of new production LP compressor fan blades found with surfaces formed outside of design intent. Findings included sharp edges, burrs, and damage present in the area at the top of the shear key slots. We are issuing this AD to prevent possible multiple uncontained LP compressor fan blade failure, due to cracking in the blade root caused by increased stresses in the shear key slots.

DATES:

This AD becomes effective September 1, 2004. The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of September 1, 2004.

ADDRESSES:

You can get the service information identified in this AD from Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: [phone]; fax: [phone].

You may examine the AD docket at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA. You may examine the service information at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

FOR FURTHER INFORMATION CONTACT:

Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine And Propeller Directorate, 12 New England Executive Park; Burlington, MA 01803-5299; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

The FAA proposed to amend 14 CFR Part 39 with a proposed AD. The proposed AD applies to Rolls-Royce plc models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines with LP compressor fan blades P/N FW18548 installed. We published the proposed AD in the Federal Register on October 23, 2003 (68 FR 60627). That action proposed to require LP compressor fan blade replacement with new or previously reworked blades, or rework of the existing LP compressor fan blades.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Include Trent 884B-17 Model

One commenter requests that we add the Trent 884B-17 model to the AD applicability, as it is missing from the proposal.

We agree, and we have added the Trent 884B-17 model to applicability paragraph (c) and to Table 1. There are currently no U.S. operators of this engine model.

Include a Service Bulletin Reference

Two commenters request that we include a reference to RR Service Bulletin (SB) No. RB.211-72-E055, Revision 1, dated June 20, 2003, which contains source life information on the cycle limits specified in the proposal compliance section.

We agree, and we have added a reference to RR Alert Service Bulletin (ASB) No. RB.211-72-AE055, Revision 3, dated May 28, 2004, in paragraph (i) of the AD for informational purposes only.

Changes to SB No. RB.211-72-E055

RR revised SB No. RB.211-72-E055, Revision 2, to an Alert SB No. RB.211-72-AE055, Revision 3, issued on May 28, 2004. The bulletin changes the reference to Boeing 777-200IGW to Boeing 777-200ER as the IGW designation is old terminology. The revision also changes the limits from using the lowest limit on mixed model configurations to using a combination of the lives for mixed model configurations. We concur in part with the changes to the SB and have incorporated into the AD the changes that are pertinent. We also discovered that the Boeing 777-200IGW and 777-200ER models are not official, type-certified designations, so we removed reference to these models from the AD. The incorporated changes do not represent a substantive change in the AD compliance requirements and therefore do not require new notice of proposed rulemaking.

Conclusion

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

There are about 350 RR models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines of the affected design in the worldwide fleet. We estimate that 106 engines installed on airplanes of U.S. registry would be affected by this AD. We also estimate that it would take about 100 work hours per engine to perform blade rework, and that the average labor rate is $65 per work hour. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $689,000.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2003-NE-38-AD” in your request.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

2004-15-02 Rolls-Royce plc: Amendment 39-13736. Docket No. 2003-NE-38-AD.

Effective Date

(a) This AD becomes effective September 1, 2004.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Rolls-Royce plc (RR) models RB211 Trent 875-17, Trent 877-17, Trent 884-17, Trent 884B-17, Trent 892-17, Trent 892B-17, and Trent 895-17 turbofan engines, with low pressure (LP) compressor fan blades, part number (P/N) FW18548, installed. These engines are installed on, but not limited to, Boeing 777 series airplanes.

Unsafe Condition

(d) This AD was prompted by a number of new production LP compressor blades found with surfaces formed outside of design intent. Findings included sharp edges, burrs, and damage present in the area at the top of the shear key slots. We are issuing this AD to prevent possible multiple uncontained LP compressor fan blade failure, due to cracking in the blade root caused by increased stresses in the shear key slots.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.

Actions Required for LP Compressor Fan Blades

(f) Replace LP compressor fan blades with new or previously reworked LP compressor blades at or before accumulating the specified cycles-since-new (CSN) in the following Table 1, or rework the existing blades as specified in paragraph (g) of this AD.

(g) Rework LP compressor fan blades at or before accumulating the specified CSN in the following Table 1. Follow paragraphs 3.B.(1) through 3.B.(22) of Accomplishment Instructions of RR service bulletin (SB) No. RB.211-72-E044, Revision 1, dated May 2, 2003, to do the blade rework.

Table 1.—LP Compressor Fan Blade Replacement or Rework Schedule

For engines installed on:	Engine model:	Replace or rework LP compressor fan blades at or before accumulating
Boeing 777-300 Series	Trent 884-17	2,400 CSN.
Boeing 777-300 Series	Trent 884B-17	2,400 CSN.
Boeing 777-300 Series	Trent 892-17	2,400 CSN.
Boeing 777-200 Series	Trent 895-17	3,200 CSN.
Boeing 777-200 Series	Trent 892-17	4,100 CSN.
Boeing 777-200 Series	Trent 892B-17	4,100 CSN.
Boeing 777-200 Series	Trent 884-17	4,100 CSN.
Boeing 777-200 Series	Trent 875-17	4,100 CSN.
Boeing 777-200 Series	Trent 877-17	4,100 CSN.

(h) For engines moved between configurations, the cycles remaining may be calculated using either of the following:

(1) Subtract the total CSN from the most limiting configuration's limit from Table 1; or

(2) Calculate the cycles remaining using the following equation:

Where:

X r = Cycles remaining in current configuration.

L c = Cyclic limit of current configuration from Table 1 of this AD.

X n = Cycles accumulated in configuration n.

L n = Cyclic limit in configuration n from Table 1.

(i) Information on the source life of the cycle limits in Table 1 of this AD can be found in RR Alert SB No. RB.211-72-AE055, Revision 3, dated May 28, 2003.

Alternative Methods of Compliance

(j) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

(k) You must use RR SB No. RB.211-72-E044, Revision 1, dated May 2, 2003, to perform the blade rework required by this AD. The Director of the Federal Register approved the incorporation by reference of this service bulletin in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You can get a copy from Rolls-Royce plc, PO Box 31, Derby, England, DE248BJ; telephone: [phone]; fax: [phone]. You can review copies at FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Related Information

(l) CAA airworthiness directive 001-05-2003, dated June 20, 2003, and RR Alert SB No. RB.211-72-AE055, Revision 3, dated May 28, 2004, pertain to the subject of this AD.

Issued in Burlington, Massachusetts, on July 14, 2004.

Francis A. Favara,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.